BMW: idle problems, bmw 520i, vacuum leaks

Question
hi dont no if u can help at wicks end with this got a bmw 520i 91 with idle problems have changed the control valve but still doing the same thanks alot  

Answer
Shaun,
 There are many reasons for Idle problems on these cars.  Unfortunately we did not get the 520i in the USA, so It will be slightly different from the 525i we had.  Check for vacuum leaks first, as those are a common cause.  Spray some starting fluid around the hoses, and if you hear the engine rev, you have a vacuum leak.  This means the engine is inhaling the starting fluid and burning it.

 Good luck,
 Josh